One of the commonly utilized methods for providing external connecting terminals for printed circuit boards is the insertion of wire-wrap type pins or posts through preformed holes in the circuit boards. The wire-wrap type pins are often square in cross-section having a diagonal dimension greater than the diameter of the preformed holes into which they are forcibly inserted.
Prior art methods and apparatus for insertion of pins have varied starting with single insertion using hand tools or machines and developing into multiple insertion also using hand placement of pins in a template having guide holes located over a circuit board, then using a simple press to push the pins through matching holes in the circuit board until the top of the pins are flush with the template. Later development has eliminated hand placement of pins through use of a second template which has matching tapered holes and which is positioned over a template similar to that previously described. During operation using this later developed equipment both of the templates as well as the circuit board are vibrated to cause pins scattered over the second template to fall upright into the tapered holes before removing the second template and proceeding with the previously described pressing procedure.
During the pressing procedure of the methods described in the foregoing paragraph, the pins are without lateral support over the greater part of their length. A slight misalignment of a hole in the circuit board and the pins often results in bending of some of the pins during the pressing operation. The bent pins tend to bind in the template holes, making removal of the circuit board from the template difficult. The bent pins must be removed from the template with consequent slowing of the production time and the holes in the circuit board where the damaged pins were to have been permanently inserted must be filled with hand-inserted pins. In many cases, the holes are damaged to the extent that the board must be discarded.